Hello, syzbot found the following issue on: HEAD commit: c06a2ba6 Merge tag 'docs-5.13-3' of git://git.lwn.net/linux git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15a19709d00000 kernel config: https://syzkaller.appspot.com/x/.config?x=4e950b1ffed48778 dashboard link: https://syzkaller.appspot.com/bug?extid=45199c1b73b4013525cf userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+45199c1b73b4013525cf@xxxxxxxxxxxxxxxxxxxxxxxxx vcan0: j1939_xtp_rx_dat_one: 0xffff8880739af000: Data of RX-looped back packet (00 ff ff ff ff ff ff) doesn't match TX data (00 00 00 00 00 00 00)! ================================================================== BUG: KASAN: use-after-free in j1939_xtp_rx_dat_one+0x108d/0x1130 net/can/j1939/transport.c:1825 Read of size 1 at addr ffff888069049a8e by task ksoftirqd/2/25 CPU: 2 PID: 25 Comm: ksoftirqd/2 Not tainted 5.13.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:436 j1939_xtp_rx_dat_one+0x108d/0x1130 net/can/j1939/transport.c:1825 j1939_xtp_rx_dat net/can/j1939/transport.c:1875 [inline] j1939_tp_recv+0x544/0xb40 net/can/j1939/transport.c:2057 j1939_can_recv+0x6d7/0x930 net/can/j1939/main.c:101 deliver net/can/af_can.c:574 [inline] can_rcv_filter+0x5d4/0x8d0 net/can/af_can.c:608 can_receive+0x336/0x580 net/can/af_can.c:665 can_rcv+0x120/0x1c0 net/can/af_can.c:696 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5440 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5554 process_backlog+0x232/0x6c0 net/core/dev.c:6418 __napi_poll+0xaf/0x440 net/core/dev.c:6966 napi_poll net/core/dev.c:7033 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7120 __do_softirq+0x29b/0x9f6 kernel/softirq.c:559 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Allocated by task 20961: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:461 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:2912 [inline] kmem_cache_alloc_node+0x269/0x3e0 mm/slub.c:2948 __alloc_skb+0x20b/0x340 net/core/skbuff.c:413 alloc_skb include/linux/skbuff.h:1107 [inline] alloc_skb_with_frags+0x93/0x5d0 net/core/skbuff.c:5990 sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2356 j1939_sk_alloc_skb net/can/j1939/socket.c:858 [inline] j1939_sk_send_loop net/can/j1939/socket.c:1040 [inline] j1939_sk_sendmsg+0x6bb/0x1380 net/can/j1939/socket.c:1175 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 sock_no_sendpage+0xf3/0x130 net/core/sock.c:2854 kernel_sendpage.part.0+0x1ab/0x350 net/socket.c:3631 kernel_sendpage net/socket.c:3628 [inline] sock_sendpage+0xe5/0x140 net/socket.c:947 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364 splice_from_pipe_feed fs/splice.c:418 [inline] __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562 splice_from_pipe fs/splice.c:597 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:746 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0x9f0/0x1110 fs/read_write.c:1260 __do_compat_sys_sendfile fs/read_write.c:1346 [inline] __se_compat_sys_sendfile fs/read_write.c:1329 [inline] __ia32_compat_sys_sendfile+0x1dd/0x220 fs/read_write.c:1329 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline] __do_fast_syscall_32+0x67/0xe0 arch/x86/entry/common.c:143 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:168 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Freed by task 20: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:212 [inline] slab_free_hook mm/slub.c:1581 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1606 slab_free mm/slub.c:3166 [inline] kmem_cache_free+0x8a/0x740 mm/slub.c:3182 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:684 __kfree_skb net/core/skbuff.c:741 [inline] kfree_skb net/core/skbuff.c:758 [inline] kfree_skb+0x140/0x3f0 net/core/skbuff.c:752 j1939_session_skb_drop_old net/can/j1939/transport.c:333 [inline] j1939_xtp_rx_cts_one net/can/j1939/transport.c:1394 [inline] j1939_xtp_rx_cts+0xb59/0xec0 net/can/j1939/transport.c:1433 j1939_tp_cmd_recv net/can/j1939/transport.c:2001 [inline] j1939_tp_recv+0x8be/0xb40 net/can/j1939/transport.c:2067 j1939_can_recv+0x6d7/0x930 net/can/j1939/main.c:101 deliver net/can/af_can.c:574 [inline] can_rcv_filter+0x5d4/0x8d0 net/can/af_can.c:608 can_receive+0x336/0x580 net/can/af_can.c:665 can_rcv+0x120/0x1c0 net/can/af_can.c:696 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5440 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5554 process_backlog+0x232/0x6c0 net/core/dev.c:6418 __napi_poll+0xaf/0x440 net/core/dev.c:6966 napi_poll net/core/dev.c:7033 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7120 __do_softirq+0x29b/0x9f6 kernel/softirq.c:559 The buggy address belongs to the object at ffff888069049a40 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 78 bytes inside of 232-byte region [ffff888069049a40, ffff888069049b28) The buggy address belongs to the page: page:ffffea0001a41200 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888069048c80 pfn:0x69048 head:ffffea0001a41200 order:1 compound_mapcount:0 flags: 0x4fff00000010200(slab|head|node=1|zone=1|lastcpupid=0x7ff) raw: 04fff00000010200 ffffea0001ad8c08 ffffea0001b09508 ffff8880127cc500 raw: ffff888069048c80 0000000000190015 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x52a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 8624, ts 272925890505, free_ts 272857357828 prep_new_page mm/page_alloc.c:2358 [inline] get_page_from_freelist+0x1033/0x2b60 mm/page_alloc.c:3994 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5200 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1644 [inline] allocate_slab+0x2c5/0x4c0 mm/slub.c:1784 new_slab mm/slub.c:1847 [inline] new_slab_objects mm/slub.c:2593 [inline] ___slab_alloc+0x44c/0x7a0 mm/slub.c:2756 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2796 slab_alloc_node mm/slub.c:2878 [inline] slab_alloc mm/slub.c:2920 [inline] kmem_cache_alloc+0x34b/0x3a0 mm/slub.c:2925 skb_clone+0x170/0x3c0 net/core/skbuff.c:1497 dev_queue_xmit_nit+0x3a5/0xa90 net/core/dev.c:2413 xmit_one net/core/dev.c:3649 [inline] dev_hard_start_xmit+0xad/0x920 net/core/dev.c:3670 sch_direct_xmit+0x2e1/0xbd0 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x4ba/0x15f0 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:136 [inline] qdisc_run include/net/pkt_sched.h:128 [inline] __dev_xmit_skb net/core/dev.c:3856 [inline] __dev_queue_xmit+0x142e/0x2e30 net/core/dev.c:4213 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0xeec/0x21f0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x35/0x200 net/ipv4/ip_output.c:318 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1298 [inline] __free_pages_ok+0x476/0xce0 mm/page_alloc.c:1572 unfreeze_partials+0x16c/0x1b0 mm/slub.c:2374 put_cpu_partial+0x13d/0x230 mm/slub.c:2410 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:438 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:2912 [inline] slab_alloc mm/slub.c:2920 [inline] __kmalloc+0x1f7/0x330 mm/slub.c:4063 kmalloc include/linux/slab.h:561 [inline] tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x272/0x380 security/tomoyo/file.c:771 tomoyo_file_open security/tomoyo/tomoyo.c:313 [inline] tomoyo_file_open+0xa3/0xd0 security/tomoyo/tomoyo.c:308 security_file_open+0x52/0x4f0 security/security.c:1633 do_dentry_open+0x358/0x11b0 fs/open.c:813 do_open fs/namei.c:3361 [inline] path_openat+0x1c0e/0x27e0 fs/namei.c:3494 do_filp_open+0x190/0x3d0 fs/namei.c:3521 do_sys_openat2+0x16d/0x420 fs/open.c:1187 do_sys_open fs/open.c:1203 [inline] __do_sys_open fs/open.c:1211 [inline] __se_sys_open fs/open.c:1207 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1207 Memory state around the buggy address: ffff888069049980: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888069049a00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888069049a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888069049b00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff888069049b80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
